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25 September 1989, Volume 6 Issue 3 Previous Issue    Next Issue

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EFFECT OF EQUATION OF STATE ON THE STELLAR CORE COLLAPSE Wang Yiren, Li Hong, Yao Jin, Wang Weizhong 1989, 6(3): 257-267.  Abstract ( )   PDF (707KB) ( )   The analysis contrasting the feature of BBAL's equation of state (eos) with the feature of equation of state EOS(1) is presental. At range of low density of matter(ρ<1011g cm-3), the chemical potential of neutron and proton of BBAL's(eos) differs notablly from EOS(1).This results in that two equations of state mentioned above differ greatly in abundance of free neutron and free proton at low density.The difference between the balance expression for finite temperature correct (thermal effect) and for "zero temperature appoximation" has been investegated.The effect for finite temperature correct on the chemical potential of neutron and proton is small, but the effect on the mass number and charge number of the average heavy nucleus is marked.Having taken 15M① model of weaver et al.as initial model,the collapse process of stellar core between the onset of collapse and core bounce has been calculated by using both the (eos) of BBAL and EOS(1).The results show that the difference betwean the calculational results of stellar collapse (at ρc~1014g cm-3) with EOS (1) and with BBAL's (eos)is not so large, in spite of that BBAL's (eos) differ greatly from EOS(l) in abundance of free nucleon at low density. The difference between calculational result (at ρc~1014g cm-3) of stellar collapse resulting from finite temperature correct and "zero temperature approximation" for both BBAL's (eos) and EOS(l) is more notable.

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NUMERICAL SIMULATION OF 14 MEV NEUTRON POINT SOURCE IN FINITE SPHERE Fu Shangwu 1989, 6(3): 268-276.  Abstract ( )   PDF (469KB) ( )   Physical experiments and numerical calculation of point source are important for studying reactor shielding and radiation effect, and for investigating the neutron parameters and computaional methods. In this paper, several typical physical experiments about point source of 14 MeV neutron have been calculated by the two-dimensional discontinuous finite element procedure. The calculated results are compared with the experimental resuts. The agrecement is satisfactory.

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TWO DIMENSIONAL SIMULATION OF THE TRANSONIC FLOW OVER NACA 0012 AIRFOIL Chen Rangfu 1989, 6(3): 277-288.  Abstract ( )   PDF (697KB) ( )   A method which Combines the numerical flux of high accurate TVD scheme with multistage method in time approaching is developed to calculate the problems of 2-D steady flow. Some special treatments are given to accelerate convergency. The numerical results of transonic flow over NAGA 0012 airfoil are obtained by this method. They show that this method is high accurate, of high resolut-ion nd time-saving.

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A GCM STUDY ON THE EVOLUTIONS OF TWO MONTHS' CLIMATIC MEAN CIRCULATION Jiang Dayong, Yang Meiyu, Min Wei 1989, 6(3): 289-301.  Abstract ( )   PDF (856KB) ( )   In this paper, the two months' integration about a global atmospheric circulation model including many physical climatic processes has been made by the global climatic mean data sets in January. The results show that the seasonal circulation systems and the steady active centres are fairly simulated by this model. And the variation of kinetic and internal energy with time show that the computation tends to be stable, consequently, it is expected that this model can be used to simulate, and be capable of simulating the climate changes on time scale of months to years.

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PROPERTIES OF THE SURFACE DIFFUSION AND THE EFFECTS OF THE SURFACE DEFECTS FOR H ON Nl SURFACES-EAIVl STUDIES Cao Peilin, Shi Danhua 1989, 6(3): 302-308.  Abstract ( )   PDF (492KB) ( )   The properties of the surface diffusion (SD) and the effects of the surfaces defects are studied using the cluster models and the embedded atom method (EAM).The results show that the activation energies of SD of H on Ni(100),(110) and (111) are 0.152eV,0.343eV and 0.142eV respectively.A adsorbeded Ni atom on Ni(100) is a trap while a vacancy is a barrier.A step on Ni(100) will increase the potential barrier and activation energy for the diffusing H atom across this step, and causing the anisotropy of SD of H on the stepped Ni surface.

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THE METHODS OF FRACTIONAL STEPS FOR SYNTHESIZING TWO DIMENSIONAL THEORETICAL SEISMOGRAMS He Bairong, Feng Deyi, Wang Zhanbiao, Ge Xiaobin 1989, 6(3): 309-320.  Abstract ( )   PDF (672KB) ( )   Some methods of fractional steps for solving initial-boundary problems of two dimensional elastic wave equations which describe the P-SV wave propagation generated by linear compressional source in the 2-D hemi-indefinite space with discontinuous coefficients are discussed. A boundary condition is provided by the contribution of source. For examining the efficiency of these methods, two calculation examples are given.

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SOLUTION OF THE N-S EQUATION OF THE STEADY INCOMPRESSIBLE VISCOUS FLOW WITH MARCHING-ITERATIVE METHOD Su Mingde, Chen Shanli 1989, 6(3): 321-334.  Abstract ( )   PDF (664KB) ( )   The marching-iterative method(MIM) is extended to solve the N-S equation of the steady incompressble viscous flow. The general formula in arbitrary curved coordination are also given.The MIM sis used to calculate the flows in a cavity and around a cylinder.The reults show that the speed of convergency of this method is rapid and the satisfactory results can be obtained from this method.

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SOLILARY WAVE SOLUTION GENERATED BY MOVING BOUNDARY Lu Qiuqiang 1989, 6(3): 335-339.  Abstract ( )   PDF (266KB) ( )   A finiti-differnce scheme for the moving boundary problem of Boussinesq's equation is presented. Various boundary conditions are used. The numerical results show the existance of the solitary wave's solution.

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HUMERICAL SOLUTION OF THE REGULARSZEB LOG-WAVE EQUATION BY PETROV-GALERKIN FINITE EIEMENT METHOB Tang Shimin, Wang Wei 1989, 6(3): 340-346.  Abstract ( )   PDF (423KB) ( )   A numerical solution of the initial value problem of regularized long-Wave equation (RLW Equation) was made by a Petrov-Galerkin finite elemnte method. The numerical resuts are consistent with the exact solution of propagation of single solitary wave, due to second-order and fourth-order accuracy for the time and spacing variable respectively. For the collision of two solitons, there is a slight oscilatoiy wave trail after their collision, so it doesn't have the quality of soliton strictly.

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SPACE-CHARGE EFFECTS IN MICROWAVE FREE ELECTRONLASER Yang Zhenhua, Tian Shihong 1989, 6(3): 347-354.  Abstract ( )   PDF (501KB) ( )   A 3-dimensional numerical simulation code for microwave FEL in which space-charge force have been in eluded approxi matelv is worked out. The code constitutes of the electrons' energies and pandermotive phases according to the averaged single-particle equations derived by KMR, and the fields according to the paraxial wave equation. The particle motion is fully three-dimensional. The field solver is accurately three-dimensional for microwave simulation. The simulated results show that longitudinal space-charge force reduce the gain and saturation power about 15%,and increase the synchrotron period of the electrons.

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DEFORMATION OF A LAYERED ELASTIC SYSTEM BY GENERAL SURFACE LOADS Pan Ernian 1989, 6(3): 355-365.  Abstract ( )   PDF (685KB) ( )   A general and considerably simple analysis, i.e. presented the propagator matrix method in two systems of vector functions is to solve the layered isotropic elastostatic problem. This approach avoids the complicated nature of the problem. The analytical expressions of displacement and stress components at any point of the medium by general surface loads are obtained in these two systems. Numerical examples given verify that the present formulation is correct, and also show that when the modified Padé approximant technique is used in the numerical integration the present method is particularly efficient and easy to apply in practice.

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AN IMITATIVE CALCULATION OF W/C, Mo/Si ARTICIFIAL MULTILAYERED FILMS' STRUCTURES AND PROPERTIES AS X-RAY MONOHROMATORS Liu Wen, Liu Wenhan, Wu Ziqin 1989, 6(3): 366-370.  Abstract ( )   PDF (317KB) ( )   An imitative calculation on W/C,Mo/Si artificial multilayered films,have been made.The influences of total period numbers and deviation of period thickness on X-ray diffraction peak were given. Two difference deviations, random fluctuation and system linear deviation have been imitated, their influences on X-ray energy distinguish power have been compared.

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A SOFTWARE SYSTEM SUTEST TO TEST UNIFORMLY DISTRIBUTED RANDOM NUMBERS Zhang Jianzhong 1989, 6(3): 371-377.  Abstract ( )   PDF (404KB) ( )   The given digital sequence r1,r2,…,ri,…,rn in the interval (0, 1) on a computer, it is a important problem in the Monte Carlo computation to tost if that the digital sequence can be used as the uniformly distributed random numbers, The software system SUTEST in the statistical package SASD (a package for the Statistical Analysis of Stochastic Data) can be used to test statistical properties of the uniformly distributed random numbers in (0, 1) with 12 kinds,27 different testing methods and 61 statistics from homogeneity, randomnes,independence and simulative computing.SUTEST is developed with portable FORTRAN and can be used on a large, middle or small computer, and microcomputers too.

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GNASH AND ITS ARPLICATION IN STUDIES OF NEUTRON-NUCLEUS REACTIONS Mi Yong, Huo Yu Kun, Li Xiang Yang, Yuan Zhu Shu 1989, 6(3): 378-384.  Abstract ( )   PDF (476KB) ( )   GNASH is a comprehensive and powerful program code to calculate cross sections and emitted particle spectra in nuclear reactions, basing upon Hauser-Feshbach statistical theory with correction from pre-equilibrium effect. This paper briefs its capacities, features and theoretical models and formulae as well as reviews the progresses made in our exploring and applying this program.